French passenger jet gone missing from radar screens........

[fido]

Eric Mc said:

julian64 said:

I'll guess lightning strike and the new composite nature of the plane.

Give me an old fashioned aluminium aircraft anyday.

The A330 is mostly an "old fashioned aluminium aircraft". It only uses composites in some components such as the tailfin.

Lighning strikes do not tend to bring airliners down.
I think there is now no doubt that the aircraft broke up at altitude and fell in pieces into the ocean. What caused the breakup will be the central part of the investigation.

Frightening to think about but .. but statistically how often does a modern aeroplane suffer castastrophic structural fatigue .. i imagine that they are over-engineered so that this should never happen over a wide range of external factors (obviously except in the case of a planned explosion).

Edited by fido on Wednesday 3rd June 09:51

[Dunk76]

fido said:

Eric Mc said:

julian64 said:

I'll guess lightning strike and the new composite nature of the plane.

Give me an old fashioned aluminium aircraft anyday.

The A330 is mostly an "old fashioned aluminium aircraft". It only uses composites in some components such as the tailfin.

Lighning strikes do not tend to bring airliners down.
I think there is now no doubt that the aircraft broke up at altitude and fell in pieces into the ocean. What caused the breakup will be the central part of the investigation.

Frightening to think about but .. but statistically how often does a modern aeroplane suffer castastrophic structural fatigue .. i imagine that they are over-engineered so that this should never happen over a wide range of external factors (obviously except in the case of a planned explosion).

Edited by fido on Wednesday 3rd June 09:51

I think the last commercial airframe to suffer repeated catastrophic structural failures was the Comet - I think the lessons learned from that experience, where four or five disintegrated in flight - caused some serious changes in the way aircraft were built, and also how they were maintained/monitored for structural flaws.

[Legend83]

fido said:

Eric Mc said:

julian64 said:

I'll guess lightning strike and the new composite nature of the plane.

Give me an old fashioned aluminium aircraft anyday.

The A330 is mostly an "old fashioned aluminium aircraft". It only uses composites in some components such as the tailfin.

Lighning strikes do not tend to bring airliners down.
I think there is now no doubt that the aircraft broke up at altitude and fell in pieces into the ocean. What caused the breakup will be the central part of the investigation.

Frightening to think about but .. but statistically how often does a modern aeroplane suffer castastrophic structural fatigue .. i imagine that they are over-engineered so that this should never happen over a wide range of external factors (obviously except in the case of a planned explosion).

Edited by fido on Wednesday 3rd June 09:51

According to the BBC the wings of newly built aircraft are tested to destruction by literally bending them at stresses up to 50% greater than your average severe storm.

[mattdaniels]

Quite a few examples since the Comet. Google for Aloha airlines flight 243 if you want an example.

[Eric Mc]

No aircraft is immune from structural failure. However, the designers' task is to ensure that structural limits are not reached in normal day to day operations and over the normal expected working life of the airframe - which could be up to 30 years of service. I cannot think of any airliner designed since around 1960 that has suffered unexpected catastrophic structural failure caused by a design oversight.

The most infanous example is that of the De Havilland Comet 1 airliner which was designed in the mid 1940s. It had inherent flaws in its design which made it vulnerable to fatigue failure of the fuselage skin. These failures caused two separate explosive decopmpressions in airline service which eventually resulted in the Comet 1 being permananetly withdrawn from airline service.

The other example I can think of is that of the Lockheed Electra turboprop. A number of these aircraft experienced main wing spar failure (and total loss of aircraft) when an unexpected resonance between the engines and the metal in the spar developed at certain power settings causing the wings to fail and fall off.
The problem was solved and the Electras were modified and returned to service. Indeed, the military version of the Electra, the Lockheed Orion, continues in service to this day.

However, ANY aircraft can experience catastrophic structural failure if it experiences extreme turbulence or enters a situation where control is lost to such an extent that limiting speeds and G loadings are exceeded.

[Legend83]

mattdaniels said:

Quite a few examples since the Comet. Google for Aloha airlines flight 243 if you want an example.

That is unbelievable! Can't believe they managed to fly all the way back to the airport with loads of passengers exposed.

[Eric Mc]

Legend83 said:

mattdaniels said:

Quite a few examples since the Comet. Google for Aloha airlines flight 243 if you want an example.

That is unbelievable! Can't believe they managed to fly all the way back to the airport with loads of passengers exposed.

That was a pretty freakish episode and not down to a particular design fault of the 737. As far as I know, of the over 6,000 737s built, this is the only one where this happened.
It was caused by the fact that, in terms of pressurisation cycles, that particular aircraft was the "oldest" operating 737 at that time AND it had performed all its work in a damp, salt water environment (i.e. island hopping in Hawaii).
This accelerated the corrosion process beyond the norm.

[Invisible man]

If anything it is testimony to the structural integrity of the 737 to withstand such a catastrophic failure

[Rach*]

Legend83 said:

mattdaniels said:

Quite a few examples since the Comet. Google for Aloha airlines flight 243 if you want an example.

That is unbelievable! Can't believe they managed to fly all the way back to the airport with loads of passengers exposed.

[john_p]

Legend83 said:

According to the BBC the wings of newly built aircraft are tested to destruction by literally bending them at stresses up to 50% greater than your average severe storm.

http://www.youtube.com/watch?v=pe9PVaFGl3o

From 1995, this is the wing load test on the Boeing 777.

[Traveller]

Eric Mc said:

The other example I can think of is that of the Lockheed Electra turboprop. A number of these aircraft experienced main wing spar failure (and total loss of aircraft) when an unexpected resonance between the engines and the metal in the spar developed at certain power settings causing the wings to fail and fall off.
The problem was solved and the Electras were modified and returned to service. Indeed, the military version of the Electra, the Lockheed Orion, continues in service to this day.

One of the first turbo daks, turboprop dakotas had a similar failure, the rear tailplane suffered a complete failure due to the much higher frequency vibrations produced by the new turboprop engines. Needed additional strengthening round the tailplane and elevator area, but not heard of any other loses of turbo daks since that early one, through structural failure anyway. Which is pretty amazing on a plane which could be over 70 years old.

[Legend83]

Aside from the obvious tragic circumstances, the worst part of this disaster is that it may be impossible to fully conclude on what the cause was and therefore make any constructive improvements to avoid the 'cause' in the future.

Unless they can trace the majority of bits from the aircraft it is pot luck if they find the key areas.

[smack]

Eric Mc said:

Legend83 said:

mattdaniels said:

Quite a few examples since the Comet. Google for Aloha airlines flight 243 if you want an example.

That is unbelievable! Can't believe they managed to fly all the way back to the airport with loads of passengers exposed.

That was a pretty freakish episode and not down to a particular design fault of the 737. As far as I know, of the over 6,000 737s built, this is the only one where this happened.
It was caused by the fact that, in terms of pressurisation cycles, that particular aircraft was the "oldest" operating 737 at that time AND it had performed all its work in a damp, salt water environment (i.e. island hopping in Hawaii).
This accelerated the corrosion process beyond the norm.

I remember that one at the time, amazing only one died. Also the problems they had with the cargo doors on 747's years ago, which resulted in the incident with United Airlines...

[CY88]

Rach* said:

Legend83 said:

mattdaniels said:

Quite a few examples since the Comet. Google for Aloha airlines flight 243 if you want an example.

That is unbelievable! Can't believe they managed to fly all the way back to the airport with loads of passengers exposed.

+1

What a view those passengers must have had from the air!

[asbo]

All things considered, they look quite relaxed.

[Eric Mc]

Traveller said:

Eric Mc said:

The other example I can think of is that of the Lockheed Electra turboprop. A number of these aircraft experienced main wing spar failure (and total loss of aircraft) when an unexpected resonance between the engines and the metal in the spar developed at certain power settings causing the wings to fail and fall off.
The problem was solved and the Electras were modified and returned to service. Indeed, the military version of the Electra, the Lockheed Orion, continues in service to this day.

One of the first turbo daks, turboprop dakotas had a similar failure, the rear tailplane suffered a complete failure due to the much higher frequency vibrations produced by the new turboprop engines. Needed additional strengthening round the tailplane and elevator area, but not heard of any other loses of turbo daks since that early one, through structural failure anyway. Which is pretty amazing on a plane which could be over 70 years old.

Not quite a design flaw in the sense that turboprop Daks are old airframes fitted with engines the original manufacturers never intended - or even imagined. DC-3s/C-47s/R-4Ds/Dakotas/Skytrains etc fitted with their original type engines are still going strong.
If anything, metal aircraft of the 1930s were definitely over enginered - mainly because metal, stressed skin construction was brand new at the time and they erred on the side of caution.

[Rob P]

A few websites say the black box "might" float.

Surely it should be designed to float as a major design requirement?! Where is it usually located? I guess the risk is that it goes down with the aircraft and sinks.

[Legend83]

Rob P said:

A few websites say the black box "might" float.

Surely it should be designed to float as a major design requirement?! Where is it usually located? I guess the risk is that it goes down with the aircraft and sinks.

Erm, I thought it was made of reinforced material and ridiculously heavy to protect it on impact? Not sure it would float.

[Eric Mc]

Legend83 said:

Rob P said:

A few websites say the black box "might" float.

Surely it should be designed to float as a major design requirement?! Where is it usually located? I guess the risk is that it goes down with the aircraft and sinks.

Erm, I thought it was made of reinforced material and ridiculously heavy to protect it on impact? Not sure it would float.

Correct. It is contained in a strong, armoured steel casing designed to withstand impact forces of a few 100 Gs. Trying to make something like that floatable as well would be rather difficult. It is also coloured bright orange (nor black).
There is also a similar device containing the cockpit voice recorder.

[Legend83]

Interesting to note that Arthur Coakley, the oil rig worker who was suspected to have been on the plane, has not been released as being on the official roster.

Coupled with his wife claiming his phone was still ringing - miracle escape perhaps?